/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.solr.bench.generators;

import java.util.function.Supplier;
import org.apache.solr.bench.SolrRandomnessSource;
import org.quicktheories.core.RandomnessSource;

/**
 * The type Lazy gen.
 *
 * @param <T> the type parameter
 */
public class LazyGen<T> extends SolrGen<T> {

  private final Supplier<SolrGen<T>> genSupplier;
  private SolrGen<T> gen;

  /**
   * Instantiates a new Lazy gen.
   *
   * @param genSupplier the gen supplier
   */
  public LazyGen(Supplier<SolrGen<T>> genSupplier) {
    this.genSupplier = genSupplier;
  }

  @Override
  public T generate(RandomnessSource in) {
    if (this.gen == null) {
      this.gen = genSupplier.get();
    }

    return gen.generate(in);
  }

  @Override
  public T generate(SolrRandomnessSource in) {
    if (this.gen == null) {
      this.gen = genSupplier.get();
    }

    return gen.generate(in);
  }
}
